CODEWITHSUNDEEP
perlmatrixsubroutinefile-read
Johnny
Johnny

Reputation: 17

Perl-printing a 2-d matrix from a file

So i am trying to read a 2-d matrix in from a file so that I can multiply two matrices together. I can get the individual rows of the matrix to print, but I can't get the subroutine to return the entire matrix. I'm not sure what I'm doing wrong. I pasted the test matrix from the file I am using:

 12345                                                                              
 67890                                                                  
 34567

The output I get is:

 final matrix is: ##THIS IS WHAT I AM TRYING TO PRINT OUT BUT I GET NOTHING
 row is:12345
 row is:67890
 row is:34567

Upvotes: 1

Views: 98

Answers (1)

Håkon Hægland
Håkon Hægland

Reputation: 40768

Here is an example:

use feature qw(say);
use strict;
use warnings;
use Data::Dumper;

{
    print "Enter filename: "; 
    chomp(my $matrix_file = <STDIN>);
    say "final matrix is:";
    my $matrix = matrix_read_file($matrix_file);
    print Dumper($matrix);
}

sub matrix_read_file {
    my ($filename) = @_;

    my @matrix;
    open (my $F, '<', $filename) or die "Could not open $filename: $!";
    while (my $line =<$F> ) {
        chomp $line;
        next if $line =~ /^\s*$/; # skip blank lines
        my @row = split /\s+/, $line;
        push @matrix, \@row;
    }
    close $F;
    return \@matrix;
}

If you give the following input file:

1 2 3 4 5
6 7 8 9 10

The program outputs:

final matrix is:
$VAR1 = [
          [
            '1',
            '2',
            '3',
            '4',
            '5'
          ],
          [
            '6',
            '7',
            '8',
            '9',
            '10'
          ]
        ];

Upvotes: 1

Related Questions